Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
xang o » lang o, tang o, dang o
hac su » hay su, tac su, hoach su
vi cua » vai cua, di cua
o hai » co hai, so hai, o lai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty xang o hai. hieu van ((hac su) OR (hoc su)) van hanh vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty xang o hai. hieu van ((hac su) OR (hoc su)) van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ty xang o hai. hieu van ((hac su) OR (hoc su)) van hanh vi cua tre*.